The present invention relates to three-dimensional pre-fabricated structural elements for building habitation units or residences.
It is known that in the last years, due to the ever-growing cost of labor in the building industry, some erecting yards have been reorganized to use prefabricated products to reduce the incidence of labor costs on the total cost of a house. Accordingly improved pre-fabricated structural elements have been designed for reducing the actual masonry work, by mainly reducing the number of fastening and sealing operations required for the set-up of such pre-fabricated elements.
However the solutions so far adopted have only partially solved the basic problems involving costs and time of manufacturing houses, which according to the social-economic requirements of each country, should be respectively low cost and short time for erection.
In the past, the pre-fabricated structural elements for the building industry have been to a great extent exemplified in substantially bi-dimensional structures which although they may have afforded some advantages concerning the manufacturing costs, nevertheless have left nearly unchanged the incidence of labour costs, due to the high number of operations which are necessary, such as assembling, welding, fastening, sealing, etc.
Three-dimensional pre-fabricated elements have also been designed and probably sometimes manufactured and employed for building residences in order to reduce the assembling costs. Such structural elements are disclosed and claimed, among others, in U.S. Pat. Nos. 3,587,197 to Renfro; 3,694,977 to Vernan; 3,775,919 to Fulton et al.
A method of erecting multistory buildings employing such three-dimensional elements is disclosed by U.S. Pat. No. 3,462,908 Wysocki.
Renfro Patent relates to a room structure in which a plurality of room modules is adapted to be cantilever supported from a center support means. Obviously there are transportability problems, due to the difficulty of carrying the full room sized modules from the factory to the erecting yard, as they are of large size and of different shape. U.S. Pat. No. 3,694,977 (Vernan) proposes the assembly of an entire floor in a modular row house by employing pre-fabricated units, which are each one-half of an entire floor, or two half-sections forming the rooms of each multiroom floor plan adapted to be joined together.
The transportability problems mentioned above can be partially solved by the structural elements made according to the above-mentioned U.S. Pat. No. 3,775,919, which are of smaller size, but this disclosure is accompanied by the inconvenience of and necessitating for providing a covering panel to be mounted on each element for completing a room.
However, all the structures according to the cited Patents and other known art do not allow to provide for the most efficient handling in relation with the manufacturing, transportation and assembling operations. Furthermore, such three-dimensional structures of the prior art are not self-supporting and need special arrangements and costly assembly operations when multistory building are to be erected, for the vertical securement of an upper element relative to a lower element.